I used white marble chip rocks about 4 years ago in landscaping around my house. Since then they have become discolored, dirty-looking, and I need advice on how to clean them without damaging the bayberry bushes that have been planted in them and the surrounding plants in the area. I was thinking of washing them, but the soap may damage the plants. Help!! I can't find anything on the Internet regarding maintenance and cleaning of these chips. Thanks for any helpful hints.

A little soap won't hurt the plants but hot water and a lot of soap will. I'm guessing the dirt may be algae and it takes a lot of elbow grease to scrub that off. If a power washer won't clean them without kicking up too much gunk you will most likely need to take them out (or at least the top layer) and wash them with vinegar, or an acid etch soap or bleach water and then throughly rinse them to dissolve the cleaner. Also marble chips will react with an acid because of the mineral composition so I wouldn't have a strong acid solution otherwise you may dissolve part of them away!